Dr. Jersey Chen is an assistant professor of cardiology at Yale University. His goal is to become an independent clinician scientist focused on applying rigorous research methods to improving the quality and efficiency of cardiovascular care in our health system. To accomplish this goal, he will enroll in courses pertaining to advanced statistical methods in hierarchical general linear modeling and instrumental variables analysis, receive structured mentoring by senior investigators, and develop research regarding geographic variation in the use of imaging associated with stress testing and their relationship to clinical outcomes and costs. This research proposal seeks to provide policymakers with a better understanding of contemporary geographic variation in the use of imaging with stress testing and its relationship with patient outcomes and societal costs. There has been substantial growth in the volume and cost burden of cardiovascular imaging studies, in particular imaging associated with stress testing. Studies suggest that imaging stress tests are often inappropriately ordered in the outpatient setting. However, there is limited data quantifying the extent of geographic variation in the use of imaging with stress testing in contemporary clinical practice. In addition, the clinical and non-clinical factors associated with regional differences are not well understood. Whether regions with higher use of imaging with stress testing have better outcomes is unknown; however, higher use of imaging is almost certainly to be strongly associated with increased costs. Geographic variation presents an opportunity for a comparative effectiveness study to examine how imaging intensity impacts clinical and financial outcomes. This research speaks directly to Agency for Health Care Research and Quality's goal of improving quality and efficiency in our health care system. The specific aims are to: 1) quantify geographic variations in the use of imaging with stress testing for outpatients; 2) identify clinical and non-clinical factors associated with the use of imaging with stress testing; and 3) determine how imaging with stress testing is associated with clinical and financial outcomes. This proposed project and the career development plan will provide Dr. Chen a foundation for a successful career as an independent investigator in cardiovascular outcomes research. Understanding whether differences in use of imaging with stress testing across geographic regions are associated with differences in patient outcomes or costs can help improve effectiveness and efficiency in our health care system.